Android : AndroidManifest.xml description

What is and usage/purpose of androidmanifest.xml file

Android Application Descriptor File - AndroidManifest.xml

Each Android application has a manifest file named AndroidManifest.xml in the project's root directory. It descibes the application components.

For example, our "Hello" application, with an activity HelloAndroid, has the following manifest (generated automatically by the Eclipse ADT):

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.mytest"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" 
                 android:label="@string/app_name">
        <activity android:name=".HelloAndroid"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

• The <manifest> element specifies the package name. It contains one <application>element.
• The <application> element specifies the icon and label used in mobile device's "apps" menu. It contains one ore more <activity> elements.
• This application has one activity named HelloAndroid. The <activity> element declares its program name (.HelloAndroid where '.' is relative to the packagecom.mytest); and label (displayed as window title). It may contain <intent-filter>.
• The <intent-filter> declares that this activity is the entry point (android.intent.action.MAIN) of the application when launched (android.intent.category.LAUNCHER).

Beside declaring the application's components, it also provides references to external libraries, and specifies the permissions.